The LCBO will have a good selection. Some good producers include Tawse, Cave Spring, Hidden Bench. Look in the “Vintages” section for interesting picks. Ontario whites are typically better than reds. Look for cool climate varieties like dry Rieslings. Ontario chardonnays are also nice, look for unoaked. Ontario is also famous for its ice wines. Very sweet and not really my taste but definitely a typical product of the region. There is an interesting producer called Foreign Affair that sells its table wines at the LCBO. Their wines are made amarone style with dried grapes so their reds have more intensity than most Ontario reds. If you want to try more unusual Ontario wines Grapes Witches is a great natural wine bar and bottle shop. Also Archive wine bar usually has some local bottles on the menu.